A stretch of the San Andreas Fault between Bakersfield and Santa Barbara, California. | Photo Credit: Carol M. Highsmith/Library of Congress
Earthquakes are classified as supershear due to a speed imbalance: specifically, when a fault ruptures faster than the travel speeds of the seismic shear waves produced. While rare, these supershear events often cause more shaking and destruction than other quakes of similar magnitudes, so better understanding the mechanics behind their occurrence has widespread implications in both seismologic fields and disaster planning efforts.
EPSS Professor Lingsen Meng and his team, including EPSS doctoral students Han Bao and Liuwei Xu, took on the investigation. Through analysis of all shallow magnitude 6.7-or-greater strike-slip earthquakes worldwide between 2000 and 2020, they found that 14% were supershear, over double the amount expected. The reason behind their startling results, Meng said, was that while scientists focus mostly on continental (land-occurring) quakes, many of these supershear quakes had occurred at sea.
To read more about Meng and his team’s methods and surprising findings, see:
https://newsroom.ucla.edu/releases/violent-supershear-earthquakes-more-common
To read their publication in Nature, see: